Kitz Forum
Broadband Related => ADSL Issues => Topic started by: broadstairs on November 25, 2008, 12:49:16 PM
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Having been playing with my connection recently and have noticed that initially my connection can use quite a few tones above 255 and as it gets into late afternoon/evening it is these tones which become too noisy and the bits are swapped to lower tones. These ofcourse do not get swapped back next day. Now I must stress that my sync rate of around 7meg is pretty stable now with an initial negotiation of a 8db SNRM (using DMT to force it) and this drops to about 6.2-6.3 over night. If I allow an SNRM initially of 6db its fine all day but drops too much in the evening.
Now my question is how likely is it that I would be able to find out why these higher tones become unreliable overnight? I've done all the usual stuff in house like wiring and ring wire and I use the master socket for my router. There seems to be no noise on the phone, although you cannot do a silent test on an LLU line.
I'd be interested in people thoughts on this please.
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At night there's generally more interference around - AM radio signals become stronger, street lights and other lighting increase, TVs get switched on, and so on. The reason these types of interference tend to affect the higher tones most is that these higher frequencies are more attenuated in the cable from the exchange to you.
Incidentally, when you get a crackly line fault, it's not uncommon for this to affect mainly the lower frequencies, because the crackles are predominantly low frequency. This type of fault can in some cases result in problems with the upstream part of the connection rather than the downstream - a problem I've encountered more than once.